In rotary internal combustion engines incorporating more than one rotor along a common eccentric shaft, the problem of supporting the eccentric shaft within the engine housing becomes more acute. Typically the eccentric shaft has been supported solely by main bearings stationed at opposite ends of the shaft. This has served satisfactorily in connection with single rotor engines since the loading arm is inadequate to seriously deflect the center of the eccentric shaft. However, as the number of rotors is increased, assembly becomes difficult and the loading arm increases with the opportunity for slight deflection in the mid region of the eccentric shaft. Since the sealing efficiency of the engine and consequent engine efficiency is dependent on close tolerances, such deflection is highly undersirable.
One approach to preventing such deflection has been to split the eccentric shaft and support each split portion with opposite end main bearings. This, of course, complicates the engine construction and promotes problems of main bearing lubrication and excess weight. Another approach by the prior art is to incorporate a center bearing in addition to the end bearings. This latter suggestion has not become a practical reality since it presents immediate problems of interrupting the normal oil flow which traditionally passes through and radially outwardly of the intermediate housing in a multi-rotor engine. If a typical known configuration is used for the intermediate bearing, it is required that it be stationed in place by the use of rods extending through and out of the intermediate housing, the latter interrupting not only the oil cooling circuit but also the water cooling circuit.